1. Field of the Invention
The present invention relates to an optical zoom lens system, and more particularly to an optical zoom tracking apparatus and method for use in the optical zoom lens system, and a computer-readable recording medium for performing the optical zoom tracking method.
2. Discussion of the Related Art
The optical zoom lens system has been widely mounted to a digital camera or digital VCR. Recently, the optical zoom lens system can also be mounted to a mobile phone or a portable multimedia player (PMP), etc. The above-mentioned optical zoom lens system can be implemented according to a variety of design methods. The most complicated design method of the optical zoom lens system may include at least 30 lens components and several mobile optical components as necessary.
However, the most basic method for designing the optical zoom lens system includes a lens or a lens group (hereinafter referred to as a “lens”), which are fixed at a specific location or be movable along an optical axis of the zoom lens system.
In the case of the above-mentioned optical zoom lens system, a focus plane of the optical zoom lens system moves from a current location to another location according to the variation of the magnifying power, such that there is a need to compensate for the movement of the focus plane in order to clearly maintain a focused image. The above-mentioned compensation of the focus-plane movement is executed by either a mechanical device capable of moving an overall lens assembly according to the magnifying power of the lens system or an optical device capable of adjusting a focus-plane location to maximally maintain the focus-plane location according to the zooming operation of the lens.
The optical zoom function for changing the magnifying power of the lens system can be implemented by moving from a current location to another location using a small-sized motor.
In other words, if the user enters a Wide-zooming signal or a Tele-zooming signal, the zoom lens moves by a drive motor. Therefore, a target-object image captured by a lens system of the camera module zooms in or zooms out, and at the same time a focal length changes. If the zoom lens moves from a current location to another location, a focus lens should be interoperable with the zoom lens, such that an in-focus status between the zoom lens and the focus lens can be maintained.
However, the above-mentioned conventional art has a disadvantage in that an unexpected defocusing problem occurs during the zooming operation of the zoom lens, resulting in the occurrence of a dim image.
And, the above-mentioned conventional art is unable to sufficiently provide the power required for implementing the optical zoom function. Therefore, in the case of a mobile phone equipped with the optical zoom lens system, a camera function is limited under the condition at least a predetermined amount of battery power has been consumed, the camera function may be limited, and the mobile phone may be compulsorily switched off during either the optical zoom tracking operation or the camera operation.